1. Field of the Invention
This invention relates to a camera having an internal recording medium for storing information representative of captured images (or video and audio), and an interface for transmitting the information from the internal recording medium to an external recording device. This invention further relates to a method of managing files of captured images (or video and audio) which is designed for use in such a camera.
2. Description of the Related Art
General cameras include video cameras, camcorders, and electronic still cameras. There is a known camera with a built-in recording medium which has a function of capturing images and sounds, a function of generating data representative of the captured images and sounds, a function of storing the generated data into the built-in recording medium, and a function of reproducing or reading the data from the built-in recording medium. Examples of the built-in recording medium are optical discs, semiconductor memories, and hard discs. The optical discs include DVDs (Digital Versatile Discs) having a diameter of 8 cm. The semiconductor memories include card-like memories and stick-like memories.
The above known camera has an interface for moving the data from the built-in recording medium to an external recording device such as a personal computer (PC). Generally, the movement of the data from the built-in recording medium to the external recording device is performed in order to prevent the built-in recording medium from overflowing. The interface is of, for example, the USB (Universal Serial Bus) type, the IEEE1394 type, or the wireless type conforming to the IEEE802.11a/b/g standards. The external recording device has a data backup area provided in a hard disc or a DVD having a diameter of 12 cm. The data coming from the camera is stored into the data backup area in the external recording device.
The data in the built-in recording medium within the camera can be copied onto the data backup area in the external recording device through the interface. Once the data has been copied, the data in the built-in recording medium is unnecessary for the user. On the other hand, as the data is moved from the built-in recording medium within the camera to the data backup area in the external recording device, the built-in recording medium is more unoccupied.
Japanese patent application publication number 2002-252825 discloses an electronic still camera and a data storage device which can be connected on a wireless communication basis or a wired communication basis using an IEEE1394 cable, a USB cable, or a network cable. The electronic still camera captures an image, and generates main data representative of the captured image and sub data representative of a thumbnail of the captured image. The electronic still camera has an internal memory. For every captured image, the electronic still camera combines main image data, thumbnail image data, and an ID (a file ID) into an image data file stored in the internal memory. The electronic still camera transmits a copy of the image data file from the internal memory to the data storage device. The above-mentioned image capture, file generation, and file copy transmission are sequentially performed after a power supply switch of the electronic still camera is changed to its ON position.
The data storage device in Japanese application 2002-252825 contains a memory unit. The transmitted copy of the image data file is recorded in the memory unit within the data storage device. After the copy of the image data file has been recorded in the memory unit, the data storage device generates a reception completion signal. The data storage device transmits the reception completion signal to the electronic still camera. In response to the reception completion signal, the electronic still camera deletes the main image data from the image data file in the internal memory.
In Japanese application 2002-252825, the electronic still camera generates a deletion command, a protection command, or a protection cancel command for selected one of image data files in the internal memory according to operator's request. The generated command contains the ID for the selected image data file. The electronic still camera transmits the generated command to the data storage device. When the transmitted command is a deletion command, the data storage device deletes the image data file, which has the same ID as that in the transmitted command, from the memory unit. Then, the data storage device generates a deletion completion signal. The data storage device transmits the deletion completion signal to the electronic still camera. In response to the deletion completion signal, the electronic still camera deletes the image data file, which corresponds to the deletion command, from the internal memory. When the transmitted command is a protection command, the data storage device inhibits the deletion of the image data file, which has the same ID as that in the transmitted command, from the memory unit. Then, the data storage device generates a protection completion signal. The data storage device transmits the protection completion signal to the electronic still camera. In response to the protection completion signal, the electronic still camera takes a step toward protecting the image data file, which corresponds to the protection command, in the internal memory. When the transmitted command is a protection cancel command, the data storage device cancel the inhibition on the deletion of the image data file, which has the same ID as that in the transmitted command, from the memory unit. Then, the data storage device generates a protection cancel completion signal. The data storage device transmits the protection cancel completion signal to the electronic still camera. In response to the protection cancel completion signal, the electronic still camera takes a step toward canceling the protection for the image data file, which corresponds to the protection cancel command, in the internal memory.
In Japanese application 2002-252825, the electronic still camera is a host (an operating or controlling side) while the data storage device is its peripheral (an operated or controlled side).
Some peripheral devices with respect to personal computers handle captured-image/sound data. In the case where a personal computer and its peripheral device are connected by a USB cable, captured-image/sound data can be transmitted from the peripheral device to the personal computer according to an application program installed on the personal computer. In more detail, when the personal computer is operated under a driver program conforming to the USB mass storage class, the personal computer recognizes the peripheral device connected thereto as one drive device. In this case, the captured-image/sound data can be transmitted from the peripheral device to the personal computer or can be deleted from the peripheral device in accordance with drag-and-drop performed on the personal computer by the user. A video camera can be an example of such a peripheral device. In the foregoing case, the personal computer is a host (an operating or controlling side) while the peripheral device or the video camera is a drive device (an operated or controlled side) connected thereto. Accordingly, the video camera can not freely control the captured-image/sound data. Thus, it is difficult for the video camera to surely detect the completion of copying the captured-image/sound data from its built-in recording medium onto the personal computer, and then delete the captured-image/sound data from the built-in recording medium.